Semiconductor device

1. A semiconductor device comprising: a heat sink having a surface with a predetermined range of surface roughening; an IC chip mounted and fixed on a specific face of the heat sink; a lead frame provided at locations surrounding the IC chip and electrically connected to the IC chip; and a sealing mold resin package for enclosing the heat sink, the IC chip, and the lead frame, wherein: a portion of the heat sink is exposed to the outside of the mold resin package; a portion of the lead frame protrudes out from the mold resin package as outer leads having a surface with a different predetermined range of surface roughening; when a specific surface area is defined as a ratio of an actual area of uneven surface to an area of an imaginary flat surface, the specific surface area of a surface of the heat sink is set at a value in the range 1.13 to 1.32; and the specific surface area of the surface of the outer leads is set at a value in the range 1.05 to 1.20 to optimize heat sink adhesion strength, resin-burr formation, and outer-lead placement on an external substrate.

2. A semiconductor device according to claim 1 , wherein the heat sink has a protrusion that bites into the mold resin package.

3. A semiconductor device according to claim 1 , wherein the IC chip is attached and fixed on the heat sink through an adhesive made of a resin, sandwiching the adhesive in conjunction with the heat sink.

4. A semiconductor device according to claim 3 , wherein the adhesive is made of a resin of an epoxy group.

5. A semiconductor device according to claim 1 , wherein the mold resin package is made of a resin of an epoxy group.

6. A semiconductor device according to claim 1 , wherein at least one of the surfaces of the heat sink and outer leads comprises an electrically plated roughened surface.

7. A semiconductor device according to claim 1 , wherein at least one of the surfaces of the heat sink and outer leads comprises an abrasion roughened surface.

8. A semiconductor device according to claim 1 , wherein at least one of the surfaces of the heat sink and outer leads comprises a sand blasted roughened surface.

9. A semiconductor device according to claim 1 , wherein at least one of the surfaces of the heat sink and outer leads comprises a chemically etched roughened surface.

10. A semiconductor device according to claim 1 , wherein at least one of the surfaces of the heat sink and outer leads comprises a laser beam roughened surface.